[Bug 2150] New: "violation" of VESA standard that causes problems

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https://bugs.freedesktop.org/show_bug.cgi?id=2150        
   
           Summary: "violation" of VESA standard that causes problems
           Product: xorg
           Version: CVS_head
          Platform: PC
               URL: http://www.vesa.org/Public/VBE/vbe3.pdf
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Driver/Vesa
        AssignedTo: xorg-bugzilla-noise at freedesktop.org
        ReportedBy: whizzter at enjoy.joint.net


i have a toshiba R100 laptop that has a trident XP4 graphics card.
i reported a problem back in april when i first found it, the XFree86
distribution has fixed this but not XOrg.

when the vesa driver tries to set a highcolor(16/32bpp) the adapter colors gets
garbled.

the cause of this is that in the file:
xc/programs/Xserver/hw/xfree86/drivers/vesa/vesa.c
in the function: VESASetMode a call is made that is not specified to be valid
according to the vesa standard.

in the end of the function there's a statement written like this:
  if (pScrn->bitsPerPixel >= 8 && pVesa->vbeInfo->Capabilities[0] & 0x01)
	VBESetGetDACPaletteFormat(pVesa->pVbe, 8);

the VESA specifications says:
"This function will return failure code AH=03h if called in direct color or YUV
mode."

the XFree86 server changed this (after i sent a notice of this bug) so that this
function is called only if "pScrn->bitsPerPixel == 8", this fixes this
particular problem but is still wrong. (the function should not be called at all
in direct color and YUV modes).

so, i suggest that you fix this bug properly (skip the call in directColor and
YUV modes) or use the quick-n-dirty patch that XFree86 used.

the q-n-d patch ( >= becomes == ) should work in 99% of the cases as i doubt
there are many cards that has 8bpp directcolor modes, but there could possibly
be cards with higher than 8bpp modes that has palettized modes that will fail.
or cards with lower bpp that "needs" 8 bits of color accuracy per channel.

please fix this. (xfree86 already has ;)

/ Jonas Lund        
   
   
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